The impact of late diagnosis of autism and ADHD on long term educational and economic outcomes.

A late autism or ADHD diagnosis can lock a child into years of avoidable struggle at school and in the job market. This project uses UK longitudinal data—from the Millennium Cohort Study, school records, and tax data—to measure exactly how much a delayed diagnosis costs individuals in lost educational progress and lifetime earnings. The researchers will then build an economic model to simulate what happens if a child receives a diagnosis and support earlier, rather than later in adolescence or early adulthood. They will also interview autistic and ADHD adults, working with them as co-researchers, to understand the real-world experience behind the numbers. If this research succeeds, it could give policymakers hard evidence to shift school screening and NHS diagnostic pathways. The economic model would show, in pounds and pence, the return on investing in earlier identification. That could change how schools, local authorities, and health commissioners prioritise resources—moving from reactive crisis support to proactive, timely intervention. The qualitative work ensures the numbers are grounded in lived reality, not just spreadsheets.